Optimize string unmarshaling

test/benchmark_test.go

@@ -226,6 +226,21 @@ func BenchmarkMarshalingByteSlices(b *testing.B) {
 	b.StopTimer()
 }
 
+func BenchmarkMarshalingStrings(b *testing.B) {
+	b.StopTimer()
+	b.ResetTimer()
+
+	var msg2 pkg1.MsgString
+	buf := make([]byte, msgStrings.Size())
+
+	b.StartTimer()
+	for range b.N {
+		msgStrings.Marshal(buf)
+		msg2.Unmarshal(buf)
+	}
+	b.StopTimer()
+}
+
 var (
 	msgMixed = pkg1.MsgMixed{
 		Value1: map[string]spkg1.SubMsg{
@@ -345,6 +360,10 @@ var (
 			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
 		},
 	}
+	msgStrings = pkg1.MsgString{
+		//nolint:lll
+		Value: "fdfsdfdsgfdlghfdkghkdfhkdfhkjghdfkhgkjdfhgkjdfhkjdgfhkjhdfkjhgkjdfhkjdfhkjdfhkjhfdkjhkjdfhkjdfhkjfdghkjhfdkjhgkjdfhkjdfhkjghfdkjhgdfkjhkjfdhkjfhkjghdfkjhdfkhgkjsfysdfydgdfkghdfkjghkfd",
+	}
 )
 
 var _ iface = implValue{}

types/tstring/builder.go

@@ -71,6 +71,7 @@ func (b Builder) MarshalCodeTemplate(_ *uint64) string {
 
 // UnmarshalCodeTemplate returns code template unmarshaling the data.
 func (b Builder) UnmarshalCodeTemplate(_ *uint64) string {
+	unsafe := b.tm.Import("unsafe")
 	code := `{
 	var l uint64
 `
@@ -79,10 +80,19 @@ func (b Builder) UnmarshalCodeTemplate(_ *uint64) string {
 	helpers.Execute(buf, types.UInt64Unmarshal("uint64"), "l")
 	code += types.AddIndent(buf.String(), 1) + "\n"
 
-	t := b.tm.TypeName(b.msgType, b.fieldType)
-	code += fmt.Sprintf(`	{{ . }} = %[1]s(b[o : o+l])
-	o += l
-}`, t)
+	code += `	if l > 0 {
+`
+	if b.fieldType.Name() == "string" {
+		code += fmt.Sprintf("		{{ . }} = %[1]s.String((*byte)(%[1]s.Pointer(&b[o])), l)\n", unsafe)
+	} else {
+		code += fmt.Sprintf("		{{ . }} = %[2]s(%[1]s.String((*byte)(%[1]s.Pointer(&b[o])), l))\n", unsafe,
+			b.tm.TypeName(b.msgType, b.fieldType))
+	}
+	code += `		o += l
+	} else {
+		{{ . }} = "" 
+	}
+}`
 
 	return code
 }